Recent revelations about the impacts of air pollution on our health are troubling, yet air pollution and the risks it poses to us are largely invisible. Today, the infrastructure of our regulatory institutions is inadequate for the cause: sensors are few, often far from where we live, and the results are slow to come to us. What about the air quality on your jogging route or commute? Can you be told when it matters most? Advances in computing technologies can allow us to answer these questions.

With the proliferation of personal mobile computing via mobile phones and the advent of cheap, small sensors, we propose that a new kind of "citizen infrastructure", CitiSense, can be made pervasive at low cost and high value.